1. Field of the Invention
The present invention relates generally to printing presses. More particularly, the present invention relates to a method for intaglio print making and an intaglio printing press used therein.
2. Description of Related Art
The term intaglio refers to a die used in printing that is incised so as to produce an image in relief. Generally, an intaglio printing die has incisions, depressions and recessed areas that are marked into a plate of copper, brass, iron, zinc, or even plastic or linoleum. Many different processes and techniques may be employed in making an artwork die from the substrate plate which are suitable for intaglio printing, but a discussion of these techniques is beyond the scope of this application.
The basic methods of intaglio printmaking have remained relatively unchanged for centuries. Once an image has been incised onto a plate, ink is spread on the plate and forces it into the recessed areas of the plate. The surface is wiped clean of ink, leaving only the ink in the recessed areas of the plate. The plate is then placed in a special press and the paper that will receive the intaglio print is registered, face down, on the plate. It should be mentioned that one characteristic of intaglio prints that make them so desirable is the plate mark received in the paper from the outline of the plate, so care is taken that the paper is registered correctly to the plate. Often the paper is dampened to make it receptive to the ink and more supple so that the paper can more easily be pressed into the incised marks (dampening the paper also enhances the print mark). One or more felt blankets are placed over the paper in preparation for the press. The press applies direct pressure to the felt, which compresses the felt, and more importantly, the paper into the inked relief of the image on the plate.
Two general designs of printing presses suitable for intaglio printmaking have been used; a screw-type press that compresses the entire surface of the artwork between two flat plates, and a cylinder-type press that applies rotational pressure on the artwork at a point between two larger cylinders and simultaneously feeds the artwork plate, paper and felt in the direction of rotation. The screw-type press design has been in continuous use since the fifteenth century. It is simple to operate, relatively easy to maintain and has relatively few wear parts to replace. One major drawback in the screw-type design is that because force is simultaneously applied over the entire surface area of the work surface, the working pressure is inversely proportional to the surface area of the workpiece. The larger the work surface, the lower the amount of pressure that can be generated from the force applied by the screw. As a practical matter, the performance of most screw-type designs drops off considerably over a few hundred square inches of surface area.
Cylinder-type intaglio printing presses do not suffer from this shortcoming because the pressure to the workpiece is applied along a line between two cylindrically shaped rollers. Essentially, the cylinder-type design applies pressure in only one direction along the work surface, rather than across the entire two-dimensional surface area of the work surface as in the screw-type device. Because the surface area between the contact points on the rollers is relatively small, the cylinder-type design enables the operator to focus a significant amount of surface pressure with a comparatively low force applied on the rollers. Therefore, the length of the roller can be increased to accommodate larger artwork without a substantial corresponding decrease in the working pressure common to the screw-type press design.